WASHINGTON -- More than 120 members of the U.S. Congress have signed a letter calling on President Barack Obama to reengage Iran diplomatically over its nuclear program following the election of the Islamic republic's next president.

The letter's authors -- a bipartisan pair of lawmakers, Charles Dent (Republican-Pennsylvania) and David Price (Democrat-North Carolina) -- plan to send it to the White House on July 19.

The letter has the signatures of about a quarter of the members of the House of Representatives and is being described as an important move for diplomacy with Iran.

Yet analysts say it doesn't represent a dramatic shift of opinion within Congress, which has been pushing for tough measures against Iran.

The letter notes that while previous Iranian presidents elected on platforms of moderation have failed to deliver, "it would be a mistake not to test whether" Iranian President-elect Hassan Rohani represents a genuine opportunity for progress in U.S.-Iranian relations.

The letter says: "In order to test this proposition, it will be prudent for the United States to utilize all diplomatic tools to reinvigorate ongoing nuclear talks."

The letter also warns against taking "provocative actions" that could weaken Rohani, who has promised moderation in Iran and abroad.

Since his election, Rohani has expressed readiness for more transparency on the nuclear issue and engagement with the international community.

'An Opportunity, Not A Guarantee'

The U.S. lawmakers' letter also advises that "bilateral and multilateral sanctions must be calibrated in such a way that they induce significant and verifiable concessions from Iran."

A spokesman for Representative Price told RFE/RL that 124 congressmen, including 15 Republicans, had signed the letter by July 18. Several more members of Congress could sign the letter before it's sent to Obama.

Representative Keith Ellison (Democrat-Minnesota), the first Muslim elected to the U.S. Congress, is among the signatories. He told RFE/RL that Rohani's election could present the United States with an opportunity "to reset" its relationship with Tehran.

"It's not a guarantee -- a guarantee and an opportunity are not the same thing. But I think if there is even a chance that the United States and Iran could engage in a new relationship-building situation, then we should take it," Ellison said.

"Both are large powerful countries, and there has been a hostile rhetoric going back and forth. Why not, with the election of Mr. Rohani, see if we can reset the relations and at least begin a dialogue?"

Alireza Nader, a senior Iran analyst with the Rand Corporation, says the letter is a "significant development."

"Obviously being tough on the Islamic republic is politically valuable, hence a lot of the strong rhetoric on Tehran's policies, especially the nuclear program," he says. "But many U.S. policymakers, including members of Congress, believe that the best option in stopping Iran's nuclear drive is through a negotiated deal."

Nader believes Rohani's election provides "a unique opportunity" to resolve the nuclear crisis diplomatically. He says Rohani "may not be an ideal Iranian leader from an American political perspective, but he is pragmatic enough that the U.S. can at least attempt to work with him in order to prevent a costly military conflict."

Nothing New?

Suzanne Maloney, a former State Department expert on Iran at the Brookings Institution, says the letter is an important gesture. But she says it doesn't represent "a tsunami" in favor of a dramatic new overture to Tehran.

"I think there has always been at least a minority of support for diplomacy with Iran," she says. "But there is likely to remain a very strong majority supportive of increasing pressure on Iran so long as there is no agreement on the nuclear issue."

Maloney says any U.S. concessions on the nuclear issue will depend on Tehran's moves. "Of course Iranians want to see something dramatic on our side, but the likelihood of either the administration or certainly the Congress supporting preemptive concessions or dramatic sanctions relaxation prior to any moves on the Iranian side is just, I think, worrisomely unrealistic," she explains.

Earlier this week, Iranian Foreign Minister Ali Akbar Salehi said Tehran would be ready to resume talks on its disputed nuclear program with world powers after Rohani takes office in early August and names his negotiating team.

The current negotiating team, led by defeated presidential candidate Said Jalili, had taken a hard-line approach during previous talks, reportedly with the full support of Supreme Leader Ayatollah Ali Khamenei.

- The National Iranian American Council commends Rep. Charlie Dent (R-PA), Rep. David Price (D-NC), and all of the 131 representatives who signed a bipartisan letter encouraging President Obama to reinvigorate diplomacy with Iran. 7/20/13

- More than 120 members of the U.S. Congress have signed a letter calling on President Barack Obama to reengage Iran diplomatically over its nuclear program following the election of the Islamic republic's next president. RFE/RL's Radio Farda correspondent Fred Petrossians spoke to one of the co-authors of the letter, U.S. Representative David Price... 7/20/13

- After an initial hard diplomatic push at the beginning of his first term, President Obama has overwhelmingly relied on economic pressure over diplomacy in an attempt to force Iran to satisfy international concerns regarding its nuclear program. But economic pressure has undermined prospects for a negotiated solution ... -Ryan Costello, NIAC 7/19/13

- Could this be the year for an engagement with Iran that "is honest and grounded in mutual respect," as President Obama proposed over four years ago? That goal seems unlikely without a shift in Iranian thinking and without a change in American diplomatic and political strategy. But two developments, one in Iran and one in the region, provide reason to think that diplomatic progress might be possible. -William Luers, Thomas R. Pickering, and Jim Walsh, NY Books - 7/18/13

- Twenty-nine prominent former government officials, diplomats, military officers, and national security experts are calling on the White House to pursue direct negotiations with Iran once the country's new president, Hassan Rouhani, is inaugurated. In a letter to President Obama today, the group called the election of Iran's new president "a major potential opportunity to reinvigorate diplomatic efforts to resolve the standoff over Iran's nuclear program." - 7/16/13